Needle bar dynamic balancer



Au'g. 13, 1957 w. A.AYREs 2,802,437

NEEDLE BAR DYNAMIC BALANQER med July 14. 1954 2- sneets-sheet 1 fie. 5

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2,802,437 Y j NEEDLE BAR DYNAMIC BALANCER Waldemar A. Ayres, Lakewood, Ohio, 'assignor to White poration ofDelaware 'I Y K Application July 14, 1954, SerialNo. u443,259 i i 6 claims. V(or. riz-2211)' Sewing Machine Corporation, Lakewood, Ohio, a cor- This invention relates toa sewing machiney and more particularly to an improved and novel arrangement in a sewing machine for dynamically balancing the needle bar and the actuating mechanism therefor.

One of the limitations to the operating speeds of a sewing machine is the objectionable vibrations set up by the moving parts as, for instance, a part such as the reciprocating needle bar, operating at high speeds. The magnitude of the vibrations limits the `operating speeds of the sewing machine and necessitates the `use of slower operating speeds to maintain the vibrations at a minimum and to lessen the operating noises present in the machine.

The main general object of the invention is to provide an improved dynamically balanced needle bar mechanism in a sewing machine. v

Another object is to provide in a sewing machine an improved and novel arrangement for dynamically balancing the needle bar and operating mechanism therefor which substantially eliminates vibrations in the sewing machine head occasionedby the rciprocation of the needle bar, even though the machine is operating at high speeds and thus produces aquieter and more efficient sewing machine. 1

A further object is to provide in a sewing machine an improved and novel arrangement for dynamicallybalancing the needle bar and wherein a reciprocating mass moves parallel to the reciprocating needle bar in oppositely phased relationshipthereto while said needlel bar and said mass are actuated by rotatable elements coaxial with the horizontal main shaft in the horizontal arm vof the sewing machine head.

An additional object is to provide in a'sewing machineA improved and novel means for dynamically balancing the needle bar, as referred to in the last named object, and withwhich a rotatable thread take-up coaxiallwitlrthe main `shaft may be combined and driven byfthey ptatable elements that actuate the Vneedle barand-the balancing means.

' Another object of the invention is to provide in'fa' sew-f Fig. 1 isa fragmentary view of thehorizontal arm.

of'a Vsewing machine hea-d, saidhorizontal` arm being shown partly in elevation while ythe outer or needle bar carrying or face end of the arm is shownin section to illustrate one form of. the needle ybar actuating mechanism and the dynamic balancing means embodying the present invention. i

I the opposite end of the horizontal arm from the yface in the' direction of the arrows.

i v Y 70 `Fig.` 2 `isua'sectional view Vtaken substantially on line- Y 2,802,437 Patented Aug. 13, 1957 Fig. 3 is a sectional view taken substantially on line 3--3 of Fig. 1 looking in the direction of the arrows.

Fig. 4 is a view similar to Fig. 1 but illustrates another embodiment of the invention, and

f Figs. 5 and 6 are sectional views taken, respectively, substantiallyon lines 5--5 and 6-6 of Fig. 4, looking Although only a portion of the horizontal arm l10 `is illustrated it `will be understood that the sewingzmachine head includes the usual vertical portion or` standard at end shown in Fig. 1. It'will also be understood that the vertical portion or standard `of the head extends upwardly from the ysewing machinebed and'that saidv bed mounts and supports suitable hook andlfeed mechanisms and the shafts for operating the same and which shafts are operatively interconnected to the main shaftn 11 that is rotatably mounted in suitable bearings in the horizontalarm 10,'one of such bearings being indicated at 12. i i* i Any suitable power means can be employed for operating the sewing machine. The free end of the hori` zontal arm 10 is generally indicated'as the face of the sewing machine, such face being designated herein as 13.` The facev 13 slidably supports a vertically reciprocating' needle bar 14 which carries at its lower end a needle and is so located asl to cooperate with'thehook and-feedA mechanisms previously referred to to effect a sewing oper-- -ation all as will be well understood in the art. The face end 13 of thearm also will mount any well known form` of presser foot mechanism.` f

The main shaft 11 toxthe left of the bearing 12 as viewed in Fig. 1 extends into a chamber 15 formed in the` end of the horizontal arm 10. VWithin the chamber 15 the shaft 11 has fixed thereto or integral therewith in coaxial relationship a `disk 16j The disk- 16 is provided on its face that is remoteto the bearing 12 with a pin 17 which may be integral with thedisk or rigidly secured thereto and which is eccentric tothe axis of the shaft 11- but is parallel to said shaft and will behereinafter referred to as an eccentric pin. The pin` 17 is' rigidly connected tothe right hand face, as viewed in Fig. l, of r4adisk 18` of the same size and mass as the disk 16 and located coaxially with said disk 16 and shaft 11'. The disk 18 on its `opposite facemounts an eccentric p in 19 similar to the pin 17 but 180 out of phase therewith. The pin 19 -is rigidly connected to the end of a stub shaft 20 coaxial with the shaft 11 but of larger diameter than the shaftf 11 and which is rotatablysupported in a bearing 21 andV extends outwardly of the face 13 of the horizontal arm and into a recess 22-,fformed in said face.'

A rotarythread take-upy mechanism is connected tol the outer end of the stub` shaft` 20 and comprises a diskr 23 concentrically and rigidly connected to the stub shaft: 20 and located in the recess 22 and a second disk 24V coaxial with the lirst disk but spaced outwardly therefrom and rigidly interconnected therewith by an eccentricA pinI 25.

From the foregoing description it will be seen-that rotation of the main shaft 11 simultaneously effects rotaj, tion of the disks 16 and 18, the stub shaft 20 and the disks 23 and 24 of the rotarythread take-up mechanism, all of said parts beingarranged in` coaxial relationship.,

The needle bar 14 previously referred to reciprocates in a vertical bore formed in the horizontalarm 10 below the chamber 15 andV projects into said chamber. The upper end of the needle bar 14 within the chamber 15 is provided with a Scotch yoke 26 that is rigidly connected. to the upper end of the needle bar and which has its` elongated opening extending in a horizontal direction. c f

Thezeccentric pin 19 passes through a shoe 27 that is l slidablymounted in thelelong'atedr'opening of the Scotch1A chamber hasv afse'cond vertical bore 29 .thatisin verti-` cal alignment with the bore28^andfwhich l'communicates with the chainberi15.

Ai counterbalancing fmass in"therfform of a 'rod 3 0 1 has"l its opposite ends=slidably"mountd in' theV bores4 28 and"l 29rfandextends throughthechamber 15:' The'- rod 30 interniediateitsrends and within' the'ch'amber 15' is pro-v vided'- with'afScotch" yoke"31;:thefelongatcd opening in' whichfextends horizontally;v Y

. Then eccentric pin /17 Jextends through a shoe 32 slidably mounted 1in the elongated fopening offtheScotch yoke 31.' Hence it Vvwill be-"seenthat therotation-ofthe'shaft 11 and th'efdiskl 16' imparts vertical reciprocatingmovement togtherod V30;V Asfalready:l stated; the eccentric pins'17 and 19 are 180 out of phase and hence rotation of theV main-shaftll will eect oppositely phased' reciprocation ofthe needle bar 14and the rod y30.

Thervmass of'thefrod 30 and its Scotch yoke 31 equals the mass of the needle'bar 14, its Scotch yoke 26'and the needle mounted in the lower'end of the needle bar. The disks 16 and 18 areof the same mass and are concentrically rotated whilethe eccentric pins 17 and 19 are of the same mass: Consequently the rotation ofthe shaft 11, disks 16 and.' 18 andl thev pins 17 andA 19 therewith effect dynamicallyfbalanced oppositely` phased reciprocation of the needle bar 14 and rod 30.l Thus'th'e operation of the mechanisrnand the oppositely'phased reciprocation of the dynamically balanced needle bar and rod 30 clause opp`osing vibrationsfto cancel outand the operating speeds can beV materially increasd=because of this fact.

The arrangement for dynamically balancing`the`rel ciprocating needle bar iscompact inasmuch as `the mechan ismfor reciprocatingthefnee'dle` bar and for reciprocating the 'balancingrod- 30 -is formed lof elements arranged coaxially -with the main shaft 11 and all containedin the chamber'lS. Also the' arrangementadvantageously en` ables` the rotatablethread take=up mechanism comprising thedisks 23 and 24 and the'pin 25 to be arranged coaxiallywithtlie main shaft' 11 and to be actuated by the diskA 18, and stub'shaft 2li-and located onV theoutside of the face I13 ofthe horizontal arm 102` In--Figs. 4to 6 inclusive; aditlerent form of construe* i tion'embodying the invention-is illustrated.- This-modiledform may be considered' asthe preferred embodiment.

Referring to Fig; 4i; theouterforfree end of the horizontal. arml of the'sewing machine headfisindicated at 33.` The kface end 340i 'thearm 33 extends downwardly and'is hollow and has-secured therein a bearing mas`s'35 the purpose ofwhich'will later become apparent. Y

The mainshaft inlthe' arm 33 is indicated ,at 36 and said Yshaft is operatively' connected to-the'sewing mechanism below the bed plate as described in connection with the main shaft 11. The shaft'36 is rotatably supported in the arm 33 by asuitable number of bearings, one of which is shown Yin Fig, 4,A and comprises a bearing bracket 37 secured to, o r formed integral with, the interiorof the arm -33 and provided vwith an opening mounting `a bearing sleeve' or bushing 38'.Y l a A1disk'39 has 'ahub 40 fitting the end of the.'shaft 36 andjrotatablyintertting the bearingbushing 38 and se-Y cured to the shaft` 36 as by the pin 41to rotate with said shaft'. The. disk 39V may be readily assembled'with the shaft 36,-andfhas secured "to, orfintegrafl with, its outer face an eccentric 'pin"42. g y

- The pin 42 is secured to, or integral with, the adjacent face-ofa disk4 43 `ande'islocated eccentrically'to the axi's 4 of -the-disk43whiehdn-turmiscoaxial with theadisk 39 and shaft 36. The disk 43 has secured to, or integral with, its outer face an eccentric pin 44 that is 180 out of phase with the eccentric pin 42.

The eccentric pin 44 is' eccentrically secured to, or integral with, the adjacentffaceI of a disk 45 that is coaxial with the disks 43 and 39 and shaft 36. The disk 4S on its outerface has a'central boss 46. The'disks 45, 43 and 39 and pins 44 and 42 constitute a double crank arm which maybe machined a's an 'integral member or which' can be assembled from separately' made parts and` which rotates with and forms an extension of the shaft 36.

The end face-34 of the arm 33'is provided with an opening 47 in which is -located thedisle 48 of a rotary thread take-up mechanism. This take-up mechanism also includes a second disk 49 located outwardly of, and spaced from, thedisk 48 and coaxial therewith. The disks48 and 49 are rinterconnectedrb'y an eccentricpinSl).

' The threadtake-'up vmechanism is secured coaxially to the'Y boss 46 'of'the'diski 455 by'a screw51 carried bythe diskr 48 and screwing intothedisk 45l'with1the head of the screw 51'accessible'through`- an opening 52 in the diskv 49.

The bearihg'mass- ZaSfisprovidedwith a lvertical b'ore thefupper end of which isfoutw'ardly tapered or enlarged as indicatedat53inV Figs. 4 andl 5l Thisvertical'bore' aligns with"an"openirig inthe undersideofthe face 34 and slidably'mounts a reciprocatingineedle' bar 54'which projects though` said openingfand is adapted to mount in its'lo'wer end a` needle, as will be well understood.

The upper end ofthe needle bar' 54v is slotted to provide a pair of parallel ears `55provided with aligned openings having bearing bushings therein mounting a pivot pinY 56. The lower`en'd'of a pitman arm 57 extends between the ears 55 and ispivoted on the pin 56; The

upper end of the'pitmari' arm` 57V has` a semicylindrical yoke 58 embracing' thelowerr half of the pin 44 while a vsemicylindrical.clampingcollar 59 is secured to the yoke 58 and embracestherupperrhalf'of the pin 44, aVv

suitable-bearing bushing 60 surrounding thepin 44 Within .the yoke and collar. tion ofshaft 36 reciprocates needlebar V54 through pin 44 -andpitmanarm 57, with the'niovement of the latter accommodated in the enlarged upper end 53 of the needle barbore;

The mass 35 isprovided with a larger vertical bore 61, the upper end of whichiszoutwardly tapered or enlargedas 4indicated at` 62; see Figs.v 4 and 6. A? counter"-l weight rod 63 slidably reciprocates'A in the bore 61 and has -a reduced upper end 64j which isslotted vto provide a pair-of parallellearsf-65 having-aligned openings pro` videdl with bearing, bushings andV mountingzapivot pin 66.* The-lower endof afpitman arm 67 extendsfbetween tlief ears-65--and--is,connected to lthejp'in 66; The upper end ofthe pitman arm 67-has2ahalf yoke 68 embracingfthe lower half of the pin 42. A clamping head or collar 69' is secured tothevv halfyoke-68andembraces the upper half` offthe pin- 42, abearing bushing. or sleeve 70 'surrounding thepin V42 within thefhalf yoke 68 and collar 69. It will be seen that rotation Vof shaft 36v effects reciprocation ofthe counterweight rod 63 through the pin 42 and pitmanrrarm 67, theenlarged end 62 accommodating the movement of the pitmanvarm.- Avent opening 61a may be provided in the underside of the end `34 beneath the bore 61.

It will be understood thatvthe needle barf54 and rod 673 during rotation ofshaft 36 reciprocateV simultaneously but in opposite phase. The masses ofthe rod 63 and the needle bar 54, as well as of the disks 39, 43, 45, 48 and 49 are so inter-related that opposing forces are dynamically'balanced or counterpoisedwherefore vibration is reduced to aV minimum thus`enabling higher operating,

been describedaii'd vshown fori illustrative purposes, it

will be'understood'the 'invention is susceptible of various It will be understood that rota-V modifications and adaptations within the scope of the appended claims.

Having thus described my invention, I claim:

1. In the horizontal arm of a sewing machine head, a horizontal rotatable main shaft terminating short of the free end of said arm, a iirst vertical bore extending to the underside of the free end of said arm, a reciprocable needle bar mounted in said first bore, a second vertical bore spaced from said first bore and parallel therewith, a counterbalance correlated in mass to said needle bar reciprocable in said second bore, a first disk secured to the end of said main shaft and coaxial therewith, a second disk coaxial with but spaced from said first disk and interconnected therewith by an eccentric pin extending between said disks, a third disk coaxial with said first and second disks and spaced from the latter and interconnected with said second disk by an eccentric pin extending therebetween and 180 out of phase with said first named eccentric pin, a pitman interconnecting said last named eccentric pin and said needle bar, and a second pitman interconnecting said first named eccentric pin and said counterweight, said disks and pins and pitmans being correlated in mass, as are said needle bar and counterweight, to provide counterbalancing opposing forces during rotation of said shaft and reciprocation of said needle bar and said counterweight.

2. In the horizontal arm of a sewing machine head as defined in claim 1 and wherein said first named disk is provided with a hub interttng the end of the main shaft and secured thereto and rotatable in a bearing provided interiorly of said arm.

3. In the horizontal arm of a sewing machine head as defined in claim 1 and wherein a rotary thread take-up is provided which comprises two axially spaced coaxial disks interconnected by a pin extending therebetween adjacent their circumferences, said rotary thread take-up being secured to said third disk coaxially therewith and having one of the disks of the take-up located in an opening formed in said arm and the other disk thereof together with the pin interconnecting said disks of the take-up located exteriorly of said arm.

4. In the horizontal arm of a sewing machine head, a rotatable horizontal main shaft, a vertically reciprocal needle bar, a vertically reciprocal counterbalance correlated in mass to said needle bar, and operative connections between said shaft and said needle bar and said counterbalance to impart to said needle bar and counterbalance oppositely phased reciprocation from the rotation of said shaft and including identical disks coaxial with said shaft and spaced axially with respect to each other and located beyond the end of the shaft, with said disks interconnected by an eccentric pin and with one of said disks connected to said shaft and the other of said disks mounting an eccentric pin on the face thereof remote to said first named pin and displaced therefrom, the eccentric pin interconnecting said disks being operatively connected with said counterbalance and the second named eccentric pin carried by said other disk being operatively connected with said needle bar.

5. In the horizontal arm of a sewing machine head as defined in claim 4 and wherein a chamber is formed in the free end of said arm and said horizontal rotatable main shaft terminates in said chamber, a vertical bore extending from said chamber to the under side of said arm, said vertically reciprocal needle bar being mounted in said bore and having its upper end located in said chamber and formed with a Scotch yoke, a vertical bore spaced from said first bore in horizontal parallel alignment therewith and extending from said chamber to the underside of said horizontal arm, a third bore in said horizontal ann in vertical alignment with said second bore and extending upwardly from said chamber, said vertically reciprocal counterbalance being correlated in mass to said needle bar and its Scotch yoke and having rod portions reciprocal in said second and third bores and a Scotch yoke thereon being located in said chamber, said identical disks including a disk in said chamber fixed to and coaxial with said shaft, a second and identical disk in said chamber coaxial with said first disk and said shaft and spaced axially therefrom, an eccentric pin interconnecting said disks and passing through the Scotch yoke of said counterbalance, an eccentric pin carried by said second named disk and 180 out of phase with said first named eccentric pin and passing through the'Scotch yoke of said needle bar.

6 In the horizontal arm of a sewing machine head as defined in claim 5 and wherein said horizontal arm is provided at its end with a bearing bore communicating with said chamber and extending to the end of said arm and coaxial with said main shaft, a stub shaft rotatable in said bearing bore and interconnected with said second named disk by the second named eccentric pin carried by the latter, and rotary thread take-up means located exteriorly of the end of the horizontal arm and operatively connected to said stub shaft.

References Cited in the file of this patent UNITED STATES PATENTS 1,379,468 Matson May 24, 1921 1,401,561 Schler Dec. 27, 1921 2,138,862 Johnston Dec. 6, 1938 2,386,678 Backlin Oct. 9, 1945 2.718,204 Breul Sept. 20, 1955 2,760,457 Rabezzana Aug. 28, 1956 

